False claim of damages

Kimberly rental : E ********** 30 . Rented the car. Car was full of scratches. Drivers door latch was missing. When driving the car to my clients only to find out the aircon doesn't work. When returning the car i told the people who collect the car that the aircon never worked. And to discover the front left hubcap is missing. Now getting an sms at 5: 30pm saying there is over R900 in damages. Find it really ridiculous to be charged R900 for a hubcap. With the condition of the car 1) scratches 2) missing latch for drivers door 3) Aircon not working.. How do i know that the hubcap was fitted properly in the first place. Cars should be checked and properly serviced before given to clients...